Checkerwork



E. A. MCKELVY Feb. 8, 1938.

CHECKERWORK Filed July 3l, 1937 2 SheS-Sheet l E. A. MCKELVY Feb. 8, 1938.

CHECKERWOHK Filed July 31, 1937 2- Sheets-Sheet 2 Patented Feb. 8, 1938 UNITED STATES PATENT oFFlcl.:

CHECKERWOBK n Eugene A. McKelvy, Ardmore, Pa.

Application July 31, 1937, serial No. 150,843

Claims.

The principal objects of the present invention are first: to obtain improved results in the.

checkerbrick or checkerwork of regenerative chambers of heating and melting furnaces of all 5 kinds, and in hot blast stoves used in blast furnace equipment by the use of slightly modified substantially standard sizes of brick, in novel arrangement and even of only one size, and of simple design as distinguished from the use of intricate shapes of fire clay brick; second: to increase the heat transfer efficiency and also the heating surface in respect to other constructions of the type referred to and having fiues of the same average size; third: to provide for the construction of f'lues of any size by a slight change in the dimensions of the brick; fourth: to provide a checkerbrick construction which can readily be used to replace present checkerwork in any stoves now in use; fifth: to provide, when desired, a basket weave" locked brickwork of rigid construction and one in which there will be much less shifting of checkerwork than in any other present construction with which I am familiar; sixth: to insure turbulence in the flowing gases; seventh: to provide for ease in cleaning the fiues; eighth: to facilitate the job of bricklaying; ninth: to enable quick repair with standard size brick in an emergency; tenth: to facilitate the use of fillers whenever the same may be required; eleventh: to provide for iiues of any desired size and walls of any practical thickness; twelfth: to provide for by-passing gas when desired; thirteenth: to permit of zoning when desired; fourteenth: to provide bricks of a shape that can be manufactured without special equipment; and fifteenth: to permit the bricks by reason of their shape to be made of super-refractories.

Other objects of the invention will appear from the following description at the end of which the invention will be claimed.

Generally stated the invention consists of a checkerbrick structure comprising a plurality of arched and skewed bricks built up in basket and having its ends inclined toward each other in the opposite direction, upwards in the drawings, or a skewed" brick.

Fig. 2 is an end view of the brick shown in Fig. 1.

I Fig. 3 is a perspective view drawn to a reduced 5 scale and showing two of the bricks of Fig. 1 in superposed relation with their surfaces of corresponding area in contact with each other.

Fig. 4 is a top or plan view of a basket weave structure built up of the bricks referred to and l0 showing at the upper left hand portion a course of bricks which is superposed on the course of brick shown at the remaining portion of the figure; the latter part of Fig. 4 being a section on the line 4-4 of Fig. 5.

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4.

Fig. 6 is a. view similar to Fig. 4 showing a different bond in the bricks; and

Fig. '7 is a sectional elevation taken on the 20 line 1 1 of Fig. 6.

Referring more particularly to Figs. 1 to 5, the bricks employed may well be designated arched skewed bricks, meaning that their faces I are inclined towards each other in one direction and 25 their ends 2 are inclined towards each other in the opposite direction. From this it results that the area of one of the other surfaces 3 exceeds the area of the other surface 4. The surfaces 3 and 4 may be referred to as top and bottom sur- 30 faces and for clearness the surface 3 will be called the bottom surface. These bricks are laid in basket weave construction and they provide fiues 5 generally square in cross section. The fiues are of alternately increasing and diminishing cross section in the respective courses. Referring to Fig. 5 at a and considering the courses from the bottom upward the flues are of decreasing cross section, whereas at b they are of increasing cross section and this is true of all four walls defining the flue.

'I'he gradually and uniformly diminishing and increasing cross section of the fiues is in a sense a squeeze area causing small squirts, which keep the flowing gases and air swirling, so that they come in contact with all faces of the brickwork forming the fiues and there is no dead center in the column of air or gas passing thru the fiues. ,The inclined surfaces of the brickwork in the fiues form impact planes against which the gases and air are thrown rather than merely rushing by as they do in a straight wall construction.

The construction and mode of operation of the modification shown in Figs. 6 and 7 are as above described except that a basket weave structure (clean and dirty gas.

is not employed but the bricks are bonded as shown in the drawings in staggered relation.

The construction 'described is particularly adapted for use in hot blast stove construction in which apparatus, adjacent to a blast furnace, the brick work is heated by burning gases and then called upon to give up the heat for raising the temperature of the air blast on its way to the blast furnace. The construction can be used in stoves of all sizes and in the onetwothreeand four-pass types.

While large flues are used when dirty gas is burned and very small ues when entirely clean gas is used there seems to be a happy medium where a flue of 3" x3 is indicated, which answers all purposes in this construction for both In a hot blast stove where a 3 x 3" ue is desired the construction of basket weave of bricks of the desired shape provides a locked brickwork of rigid construction and one in which there will be comparatively little shifting of the checker-brick in respect to usual constructions.

For a 3X3" flue a standard 9*x3" No. 3 arch with skewed ends is employed and it serves for the entire construction. The brick is skewed large end down and the course above with the small end down in the well known basket weave construction. 'I'he brick are soV tapered and skewed as to fit one into the other one. The resulting vertical flue course has a 21/2" opening at the bottom and 41/2" above the flue with an opening of 31/2" x 31/2'l and the next course 41/2" above the opening is back to 21/2 x 21/2 and so on all thru the construction. This makes an average flue dimension of 3"X3". Asstated above, if a larger or smaller ilue is desired, the dimensions of the same brick can be changed and it will still remain a modified 9" straight in commercial use as well known to the manufacturers and`users of fire brick. Of course this description is given by way of explanation rather than limitation. It has been established that the wall thickness for the best storage of heat in checkerbrick construction is somewhere between 2" and 3" thick, that is the dimension of the walls in the described construction and it makes for increased storage capacity over other designs now in use and with which I am familiar. Where walls are less than 2 in thickness there is not the storage capacity for heat although they are more quickly heated up and in walls where the thickness is over 3 there is a lost area in the center of the wall which is of little value. In addition to the better storage capacity the described construction provides an increased heating surface due to the batter of the side walls. In the described construction the flues present plane surfaces and can be readily cleaned if clogged as by dirty gas. The fact that one simple brick shape can be used reduces the cost of the construction and lends itself to quicker repair with ordinary brick in case of an emergency.

Where the basket weave construction is employed with rectangular bottom brick it lends itself to a simpler steel grid bottom construction now in vogue than any of the intricate shapes now on the market and with which I am familiar. In cases where not enough stove capacity is available a sphere or ellipsoid or spheroid or other odd shaped filler can be used every 9" in the flue, filling to a large extent the enlarged flue at these points and not requiring any bottom support since it is held in position by the inclined sides of the checkerwork. Such'a filler block is indicated at X in Figure 6.

Where oblong flues are preferred-as they have frequently been in the past, the described checkerwork lends itself to that construction. Instead of the basket weave bond the bricks are staggered, overlapping at the ends, to give the desired length of flue, Figs. 6 and 7. In this case one brick is laid directly upon the one below it butv reversed so that they form perfect alignment. The angle of bevel of the sides and ends can be increased or diminished, thus giving any corrugated effect desired with the thought of increasing or decreasing turbulence. In this staggered bond the bricklaying is a little more difficult since the lapped joints must all be of the same size and in a course, one row will have the long ydimensions upand the next row the short dimensions up. 'In the course above the same brick are used but reversed, so that'once the bottom course has been laid out the bricklaying then becomesA almost as simple as in the basket vweave construction, and as in that case only the one brick is required for the entire system.

It will be obvious to those skilled in the art 'to which the invention relates that modifications may be made in details of construction and arrangement lwithout departing from the spirit of the invention which is not limited as to such matters or otherwise than the prior art and the appended claims may require.

I claim:

1. A checkerwork brick, structure for regenerative chambers comprising a plurality of refractory brick of the 'form of an oblong hexahedron having end surfaces of equal area inclined towards each other in one direction and having side faces of equal area inclined toward each other in the opposite direction and having the other two faces parallel and of unequal areas, said brick built up in bonded construction and providing in the structure vertical fiues of progressively increasing and diminishing cross section.

2. A checkerwork brick structure for regenerative chambers comprising aplurality of refractory brick of the form of an oblong hexahedron having end surfaces of equal area inclined towards each other in one direction and having side faces of equal area inclined toward eachother in the opposite direction and having the other two faces Aparallel and of unequal areas, said brickvbuilt up in basket weave construction with their inclined ends and inclined sides in contact with each other and providing in the structure vertical fiues of'progressively increasing and diminishing square cross section.

3. The construction substantially as described in claim 1 and provided with fillers held in position by the inclined walls which define the described cross section of the flue.

4. A checkerbrick construction comprising a plurality of -bricks each of the form of an oblong hexahedron having end faces of equal area and inclined toward each other in one direction and having side faces of equal area inclined toward each other in the opposite direction and having the two other faces parallel and of unequal areas, and said brick built up with parts of their inclined side faces in contact with each other, providing Ilues of progressively increasing and diminishing oblong cross sectional area.

5. A refractory brick of the form of an oblong hexahedron having end faces of equal area and inclined towards leach other in one direction and having side faces of equal area and inclined toward each other in the opposite direction and having the other two faces parallel and of unequal area.

EUGENE A. McKELVY. 5 

